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GHSA-66QW-VMH2-J2C2

Vulnerability from github – Published: 2026-09-03 15:32 – Updated: 2026-09-03 15:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

af_packet: Don't send zero-byte data in tpacket_snd().

syzbot reported a WARNING in __dev_queue_xmit() triggered via tpacket_snd():

skb_assert_len WARNING: at include/linux/skbuff.h:2753 skb_assert_len WARNING: at __dev_queue_xmit+0x21bc/0x4970 net/core/dev.c:4781

Call Trace: dev_queue_xmit include/linux/netdevice.h:3448 [inline] packet_xmit+0x243/0x310 net/packet/af_packet.c:276 tpacket_snd net/packet/af_packet.c:2907 [inline] packet_sendmsg+0x28d6/0x4eb0 net/packet/af_packet.c:3134

When sending 0-byte packets via TPACKET ring buffer on devices with no hard header (e.g. dev->hard_header_len == 0), tpacket_fill_skb() populates an skb with skb->len == 0 and returns 0. tpacket_snd() then forwards this empty skb to packet_xmit(), causing __dev_queue_xmit() to hit skb_assert_len(skb).

Similar checks exist in packet_snd() via commit dc633700f00f ("net/af_packet: check len when min_header_len equals to 0") and in packet_sendmsg_spkt() via commit 6a341729fb31 ("af_packet: Don't send zero-byte data in packet_sendmsg_spkt().").

Return -EINVAL in tpacket_fill_skb() when skb->len is zero to reject zero-length packets in tpacket_snd().

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80742"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-03T13:06:13Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_packet: Don\u0027t send zero-byte data in tpacket_snd().\n\nsyzbot reported a WARNING in __dev_queue_xmit() triggered via tpacket_snd():\n\nskb_assert_len\nWARNING: at include/linux/skbuff.h:2753 skb_assert_len\nWARNING: at __dev_queue_xmit+0x21bc/0x4970 net/core/dev.c:4781\n\nCall Trace:\n \u003cTASK\u003e\n dev_queue_xmit include/linux/netdevice.h:3448 [inline]\n packet_xmit+0x243/0x310 net/packet/af_packet.c:276\n tpacket_snd net/packet/af_packet.c:2907 [inline]\n packet_sendmsg+0x28d6/0x4eb0 net/packet/af_packet.c:3134\n\nWhen sending 0-byte packets via TPACKET ring buffer on devices with no\nhard header (e.g. dev-\u003ehard_header_len == 0), tpacket_fill_skb()\npopulates an skb with skb-\u003elen == 0 and returns 0. tpacket_snd() then\nforwards this empty skb to packet_xmit(), causing __dev_queue_xmit() to\nhit skb_assert_len(skb).\n\nSimilar checks exist in packet_snd() via commit dc633700f00f\n(\"net/af_packet: check len when min_header_len equals to 0\") and in\npacket_sendmsg_spkt() via commit 6a341729fb31 (\"af_packet: Don\u0027t send\nzero-byte data in packet_sendmsg_spkt().\").\n\nReturn -EINVAL in tpacket_fill_skb() when skb-\u003elen is zero to reject\nzero-length packets in tpacket_snd().",
  "id": "GHSA-66qw-vmh2-j2c2",
  "modified": "2026-09-03T15:32:15Z",
  "published": "2026-09-03T15:32:15Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80742"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1fc70b3d513bafb16b17540178870ef46e81c0bb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3fa110f9e2ea96f567f2194c673c4bc327640111"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6bcd76c134c55c697148acb5c0194e9666abdf84"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7521e691c7c4f2231634c95053281ac888d1f452"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/80a702964467b998d254f16cc61c2c9a20540c9d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/98c5914d6b7bd4b4675535908e57dea31f1efd6a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dde212f8622f5cb36223fff1ebd6e6f2a3dc61fe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f09ac5682f1bb67981fcb6ead4d3cfe439225876"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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